An American Airlines co-pilot was charged with operating under the influence of alcohol following his arrest at the Detroit Metropolitan Airport on March 26, officials said.

John Maguire, 50, is suspected of having a blood-alcohol concentration (BAC) over the legal limit. The Federal Aviation Administration (FAA) states that pilots may not operate or attempt to operate an aircraft while under the influence of alcohol; with a blood alcohol content of 0.04 percent and above; or for 8 hours after having consumed alcohol.

The FAA said on Monday that Maguire was “detained this morning under suspicion of having a BAC over the legal limit when he arrived for his flight in Detroit.”

Maguire, who lives in Pennsylvania, was scheduled on a flight from Detroit to Philadelphia, but after he was detained the flight was cancelled. The cancellation left passengers heading to their spring break stranded.

According to WXYZ, Transportation Security Administration (TSA) officers saw that the pilot was acting weirdly and alerted airport authorities.

Airport spokesman Michael Conway said the pilot failed a breathalyzer test. In custody of the Romulus police, Maguire failed a second breathalyzer test.

American Airlines told WXYZ in a statement, “This is a serious matter and we are assisting local law enforcement and the Federal Aviation Administration with the investigation. We will handle this matter appropriately as the safety and care of our customers and employees is our highest priority.”